Two Simple Capacitance Sensing Solutions

Thanks to their low cost, modularity, and reusability, measurement systems based on low cost general-purpose microcontrollers are highly attractive solutions for undergraduate courses in electrical measurements and biomedical engineering. This paper describes two such systems developed for capacitance measurement - one relying upon voltage divider and another observing charging/discharging time. The results show that both systems perform well, in spite of their simplicity and modest budget. Positive feedback from undergraduate students with specific comments and proposed improvements is presented. Furthermore, possible healthcare applications of the presented solutions for human activity recognition by wearable capacitive sensors are presented.